HELP! LSC dying/sputtering out when FX loop is engaged...

[dudleydawson]

easy right?
change the FX send/return preamp tube (V3) with a known good tube! i felt good and smart about that one...

but... FAIL.
still cutting out. sputters and fades until i get nothing.
amp comes back full force when i bypass loop.

this behavior is consistent across all wattages on both channels. it doesn't happen until i've been playing ~20 minutes.
my power tubes are in need of replacement - but i don't see how that would explain this.

tomorrow i'll start looking at other preamp tubes, but this still isn't making sense to me.
does engaging the effects loop impact the way other (non-V3) preamp tubes, or even the power tubes, operate?
what am i missing? help me!

 

[lostcause]

Clean your send and return jacks. Also the leads that you use in them.

 

[dudleydawson]

thanks... unfortunately - this is happening without cables in the jacks!

 

[lostcause]

Yes. That is correct. I know it sounds unrelated but it can still happen. I had a Fender Pro Tube Pro Reverb go down at a gig. I took it to a repairer who sent it back after cleaning out the jacks with a little Deoxit. I didnt have anything in the loop either. But I had at some stage.
It worked fine. Until the jacks got all dirty again. I cleaned them with Deoxit. Worked fine.
I have had the same thing happen to my LS. Deoxit. Try it.

 

[dudleydawson]

allright then... i'm gonna cross my fingers and give it a try! thanks for the tip!

 

[dudleydawson]

this is why the boogie board rules.
problem solved... thanks for your help!